Abstract Consistent with NICHD's goal of identifying protective factors for preventing unintended pregnancy, research is needed to understand how parenting processes influence sexual behavior among the high-risk group of offspring of teen parents. This study's significance lies in identifying which aspects of mothers' and fathers' parenting can reduce youth sexual risk in teen parent families. Its innovation rests on assessing whether the established protective influence of maternal and parenting processes on sexual behavior extends to teen parent families and on exploring variability within teen parent families, which is often overlooked. The inclusion of fathers is particularly novel, as few studies investigate their influence in teen parent families. As background, offspring of teen parents are more likely to have sex at an earlier age and become teen parents themselves than those whose parents were older when they had children (?later parents?), even after accounting for race/ethnicity and socioeconomic status. Parent closeness, disapproval of teen sex, monitoring, and communication can protect adolescents from risky sexual behavior, but it is unclear whether this influence extends to teen parent families. The absence of research is particularly stark on how fathers in teen-parent families can support adolescents' sexual health. In addition, few studies explore the heterogeneity of parenting processes within teen parent families. Using Deutsch and Gerard's theoretical framework, the current study will 1) compare the influence of mothers' and fathers' parenting practices on adolescent and emerging adult sexual behavior in teen-parent and later-parent families, and 2) explore parenting variation within teen mother families and its influence on sexual behavior. This study is based on secondary analysis of the first three waves of Add Health, providing a unique opportunity to identify teen parents through reports of age of parents and their biological children, and includes adolescents' reports of both maternal and paternal parenting processes. Regression analyses will be used to compare associations of parenting processes with sexual behavior for offspring of teen mothers (n=2076) and later mothers (n=6225) and for offspring of teen fathers (n=400) and later fathers (n=4733). Latent profile analysis will be used to explore variation in parenting processes within teen mother families and its associations with sexual behaviors. Study findings can be used to leverage and enhance maternal and paternal parenting processes in teen-parent families and will produce recommendations for how pediatricians and other health care providers can support offspring of teen parents to combat the costs of intergenerational early sex and teen pregnancy for this at-risk group.